This invention relates to multi-functional admixtures for hydraulic cement compositions and more particularly to multi-functional admixtures capable of providing not only hydraulic cement compositions having a normal water/cement ratio but also those having a small water/cement ratio simultaneously with a plurality of functional characteristics that are desirable to such compositions.
Many kinds of admixtures for hydraulic cement compositions have been known. For example, many kinds of compounds of polycarboxylic acid have been known as a dispersant capable of providing fluidity to hydraulic cement compositions, as disclosed in Japanese Patent Publications Tokko 58-38380 and Tokkai 2001-48620, Japanese Patent 2541218, and U.S. Pat. Nos. 4,946,904, 4,962,173, 5,142,036 and 5,362,829. There are several problems with these prior art admixtures, however, when they are used with hydraulic cement compositions with a small water/cement ratio. For example, it requires a long time of kneading in preparing the hydraulic cement composition, the viscosity of the prepared hydraulic cement composition is too high and its fluidity is not sufficient, the autogeneous shrinkage of the hardened object obtained from the prepared hydraulic cement composition is too large and the strength of such a hardened object is not sufficiently high.